"The side that you part your hair on sees the sun the most; this can make it get gray faster," says dermatologist Jeannette Graf. (A change will also give your hair some volume.) Protecting all your hair from UV light with a product like Rene Furterer Protective Summer Fluid spray will help preserve color.

"Optimists tend to look better as they age," says Christopher Peterson, professor of psychology at the University of Michigan in Ann Arbor and author of A Primer in Positive Psychology (Oxford University Press).

You'll reduce dark circles, perk up sallow skin, and improve your mood. "People who claim they can get by on five hours of sleep a night age more quickly than if they were getting eight or nine hours," says neurosurgeon Sanjay Gupta.